Transposons causes adaptation without Darwin


The article "Transposable element evolution in plant genome ecosystems" by Marc Pulido and Josep M. Casacuberta discusses the complex and dynamic relationship between transposable elements (TEs) and their host plant genomes. TEs are mobile genetic elements that can insert, copy, and delete themselves from the genome. They can have a significant impact on genome evolution, both positively and negatively.

The authors of the article argue that the traditional view of TEs as selfish parasites (aka "Junk DNA") that are constantly under attack by their host genomes is too simplistic. They point out that TEs are not all created equal, and that some families of TEs are more successful than others at surviving and propagating in the genome. They also argue that the host genome is not a passive victim, but rather an active participant in the coevolution of TEs.

The authors use the concept of an "evolving ecosystem" to describe the complex interactions between TEs and their host genomes. They argue that TE families can be thought of as different species, each with its own unique strategies for survival and reproduction. The dynamics of each TE family are shaped by the interactions between the family and other TE families, as well as by the environment of the host genome.

The article concludes by discussing the implications of the "evolving ecosystem" model for our understanding of TE evolution and genome dynamics. The authors argue that this model provides a more realistic and nuanced view of the TE-host relationship. They also suggest that this model could be used to develop new strategies for managing TEs in crop plants.

Here are some of the key points from the article:

  • TEs are a diverse group of mobile genetic elements that can have a significant impact on genome evolution.

  • The relationship between TEs and their host genomes is complex and dynamic.

  • TE families can be thought of as different species, each with its own unique strategies for survival and reproduction.

  • The dynamics of each TE family are shaped by the interactions between the family and other TE families, as well as by the environment of the host genome.

  • The "evolving ecosystem" model provides a more realistic and nuanced view of the TE-host relationship.

  • This model could be used to develop new strategies for managing TEs in crop plants.

Transposable elements (TEs) are a major component of plant genomes, making up as much as 90% of the DNA in some species. TEs are mobile genetic elements that can copy and paste themselves into different locations in the genome. This ability to move around can have both positive and negative effects on the host organism.

On the one hand, TEs can cause mutations that can lead to harmful or even lethal phenotypes. For example, TE insertions can disrupt genes, resulting in loss of function or misexpression. TEs can also activate oncogenes, which can lead to cancer.

On the other hand, TEs can also have beneficial effects on the host organism. For example, TEs can contribute to genome diversity, which can be important for adaptation to new environments. TEs can also provide new genetic material that can be used for evolution of new traits.

The relationship between TEs and their host genomes is complex and dynamic. TEs are constantly evolving, and their activity is influenced by a variety of factors, including the host's epigenetic state. Epigenetic regulation is a process that controls gene expression without changing the DNA sequence. Epigenetic mechanisms can be used to silence TEs, preventing them from causing harmful mutations.

In recent years, there has been growing interest in the role of epigenetics in TE evolution. Studies have shown that TEs can influence the epigenetic state of the host genome, and that epigenetic changes can in turn affect TE activity. This suggests that there is a feedback loop between TEs and epigenetics, which can have a profound impact on genome evolution.

The study of TE evolution in plant genome ecosystems is a rapidly growing field. As our understanding of this complex process continues to evolve, we are gaining new insights into the role of TEs in plant biology and evolution.

Here are some specific examples of how epigenetics can influence TE evolution:

  • DNA methylation: DNA methylation is a process that adds a methyl group to a DNA molecule. This can silence genes by preventing them from being transcribed. TEs can also be methylated, and this can inhibit their activity.

  • Histone modification: Histones are proteins that wrap around DNA to form chromatin. The way that histones are modified can affect the accessibility of DNA to transcription factors. TEs can also be associated with modified histones, and this can influence their activity.

  • Small RNA regulation: Small RNAs are a type of RNA that can regulate gene expression. TEs can be targeted by small RNAs, and this can silence their activity.

These are just a few examples of how epigenetics can influence TE evolution. As our understanding of this complex process continues to evolve, we are gaining new insights into the role of TEs in plant biology and evolution.

Transposons work outside of neo-Darwinism. Neo-Darwinism is a theory of evolution that explains how new species arise through the accumulation of mutations over time. Transposons are "chunks" of DNA not formed by Darwin's gradual mutations.

For over 30 years Neo Darwinists held that "Junk DNA" (TE) did not directly code for proteins for natural selection to act on ergo TE's were specifically excluded from evolution.

Now we know transposons can contribute to evolution in a number of ways that are not neo-Darwinian.

For example, transposons can insert themselves into genes, causing mutations that can change the function of the gene. This can lead to new traits for rapid adaptation.


For example Darwin's Icon of evolution the "Industrial Moth" in England was formed in an "instant" due to a TE that changed it's color to dark adapting it to the pollution of industrialized England. It was not due to the slow accumulation of Darwinian mutations. In addition this industrized  period of time was only for 50 years. Darwinian mutations would have taken millions of year's. NeoDarwinism works in the here and now, it could not have anticipated an event in the very distant future. Epigenetic regulation of TEs can happen in one generation.

Transposons can also move around the genome, shuffling genes around and creating new combinations of genes. This can also lead to new traits.

So, while transposons do not fit neatly into the neo-Darwinian model of evolution, they can still play a significant role in the evolution of species.

Overall, transposons are a powerful force for evolution, and they can work in a variety of ways that are not neo-Darwinian.




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